Weighing scale



Dem 21,1926. L61L569 T. H. STRACHAN WEIGHING SCALE Original iled August 1. 1925 2 Sheets-Sheet 1 Z] Ram ro: w ins 33 @l'fomwag Dec. 21 1926. 1,611,569

- T. H. STRACHAN WEIGHING SCALE Original Filed August lv 1925 2 Sheets-Sheet 2 avwwl to:

95 Li fitter/weir @W' M VDWAM Patented Dec. 21, 1926.

UNITED STATES THOMAS HENRY STRACHAN, O1? DAY'EGZI,

OHIO, ASSIGNQR TO DAYTON SCALE USM- PA'NY, OF DAYTON, @1119, A COREGRATION 013 NEW JERSEY.

VIEIGHING SCALE.

Original application filed August 1, 1925, ial 11c. 47,4?2

This invention pertains to weighing scales, being a division of my copending application Serial No. 47,172, filed August- 1, 19:25, and comprises improvements in zero adjusting devices for such mechanisms.

My present device is particularly useful in scales of the drum type in which there is a load counterbalancing member, such as a spring, together with a chart rotating device, such as a rack and pinion, in each end of the drum.

In scale of the above type the two counterbalancing members are connected by a horizontal draw bar underneath the drum, and the two racks are connected by an equalizer bar parallel with and adjacent to the draw bar. By interconnecting the draw bar and equalizer bar at their centers with an adjustable device it is possible to move the racks vertically relatively to the springs, thereby providing means for rotating the chart relatively to the fixed portions of the machine for the purpose of adjusting the chart to its zero position.

This invention relates to the above mentioned adjustable device, the principal use of which is to bring the indicator to correct zero position. My device is rugged in construction, easy to adjust, cheap to manufacture, positive in operation, and not subject to inadvertent change of adjustment due to vibration or shock while the scale is in use.

In the drawings,

Fig. 1 is a side view of a drum scale with outer casing removed.

Fig. 2 is a skeleton view of the chart, springs, racks, pinions, draw bar, equalizer bar, and the zero adjusting device, parts of the chartand adjusting device being broken away.

Fig. 3 is a side view of the device, partly in section.

Fig. 4; is a front view of the device, partly in section.

The scale comprises, in general, a base upon which is fulcrumed a base lever 75. Extending upwardly from the free end of lever 7 5 is the steelyard rod 101 which on gages a loop 102 in the lower end of frame 103 of the zero adjusting device. The upper end of frame 103 is fast to the draw bar 111 at the middle of its length.

Slidably mounted in frame 103 is a plate Serial No. 101,313.

Div-"iced and this application filed April 14,

101 which is constantly urged downwardly by spring 105 connecting the lower end of slide 104 to frame 103. Threaded into the side of frame 103 is the screw 107 inclined upwardly so that its flat inner end bears against the inclined surface or seat 106 of slide 104. When screw 107 is turned out, slide 101 is drawn down by spring 105, seat 106 being kept in contact with the end of screw 10?. When the screw is turned in, slide 10 1 is forced upwardly by the screw against the tension of spring 105. If screw 107 be not moved, slide 10 1 is held in fixer relation to frame 103 by spring 105 which holds seat 106 against the flatend of the screw.

The upper end of slide 10 1 is provided with a horizontal slot 108 having rounded edges, through w l snugly passes equalizer bar 101). F ram is also apertured at its up- 1 r) 1M1) per end as at 110, to provided clearance for rod 100, both vertically and laterally. Since frame 103 is fast to draw bar 111 it will be apparent that any vertical movement of slide 10% relative to frame 103 will move bar 100 vertically relatively to bar 111. Bar 111 is channel shaped and overlies and partly surrounds bar 109.

Pivotally connected to the outer ends of bar 109 are the upwardly extending rack bars 115 having on their upper ends racks 117 engaging pinions 130 on chart shaft 128. Supporting the outer ends of draw bar 111 are the load counterbalancing springs 113, fastat their upper ends to screws 120 which in turn are secured to the frame of the machine.

lVhen a load is placed on platform 92, which is supported in the well lrnown manner on lever 75, the free end of lever 75 draws down steelyard rod 101, adjusting frame 103, bar 109, and bar 111 against the resistance of springs 113, thereby rotating chart 1% by means of racks 117 until a position of equilibrium is reached, whereupon the operator may read the indication on the chart by the aid of any adjacent fixed part of the machine, preferably indicator wire 143 which is stretched along the front of the chart but out of contact with it, each end of wire 143 being fast to a clip 145.

If no load is on the scale platfrom the chart should indicate zero. If it does notindicate zero, screw 107 is advanced or Withdrawn until the indication is correct, whereupon the; scale is ready for use.

The action of screw 107 is communicated to the chart in a manner that will be readily apparent.

When no load is on the platform, springs 113 maintain draw bar 111 in a fiXed vertical position and as frame 103 is fast to bar 111, it is also in a fixed vertical position. hen screw 107 is turned, plate 10% moves vertically relatively to frame 103, carrying with it equalizer bar 1 09 and racks 11?. Consequently shaft 128 and chart 126 are rotated relatively to the fixed parts of the scale, such as the indicator wire, until the desired position of the chart relatively to the wire is attained.

It is to be understood that the invention is not limited to the specific details herein illustrated and described, but can be embodied in other forms without departure to draw downwardly upon the plate, and an adjustment screw threaded in the frame and hearing at its end upon an angular seat in said plate.

2. A Zero adjustment device for varying the relative connection of an equalizerrod' and an operating steelyard', said device comprising a frame member, a plate sliding therein and recessed to receive the equalizer, nd a spring connecting said plate and raine member, said plate having an angular eat therein and a screw threaded in said rame member and having a flat end bearing against saic seat, said screw by in and. out adjustment against said seat, affording. adjustment for the vertical position of said plate for the purpose described.

3. In a weighing scale, in combination, a movable chart, an immovable member, and a settable device to adjust said chart relatively to said member, said device compris ing a frame, a slidable member mounted in said frame and provided with an angular seat, a spring arranged to draw said slidable nembcr downwardly relatively to said rame, and a screw settable in said frame against said seat to move said slidable mem her in said frame against the action of saidspring.

ln testimony whereof I hereto allix my qignatur THOMAS YENRY STRAGHAN. 

